CVE-2026-21865
MEDIUMCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Lifecycle Timeline
2Tags
Description
Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, moderators can convert some personal messages to public topics when they shouldn't have access. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. As a workaround, site admin can temporarily revoke the moderation role from untrusted moderators or remove the moderator group from the "personal message enabled groups" site setting until the Discourse instance has been upgraded to a version that has been patched.
Analysis
Discourse versions before 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 allow moderators with insufficient permissions to convert private messages into public topics, potentially exposing sensitive user communications. The vulnerability affects any Discourse instance where untrusted moderators have access to moderation features. …
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Remediation
Within 30 days: Identify affected systems running versions and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.
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External POC / Exploit Code
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